Project Summary/Abstract The possibility that cognitive skills can be improved via dedicated behavioral training is a topic of substantial interest, excitement and controversy. While existing scientific results indicate that well-designed cognitive training paradigms may have the potential to effect positive real-world change in cognitive functions, contemporary approaches have been subject to increasing criticism. In particular, it has been suggested that some or all of the positive effects that have been previously attributed to cognitive training may, in fact, be related to placebo effects. This criticism stems from the fact that participants, in even the best designed cognitive training studies, cannot be truly blinded to condition. Unlike in the medical domain, where the creation of two identical pills (one active and one inert) ensures that participants are unaware of which they are receiving, in behavioral training, participants are necessarily cognizant of the fact that they are undergoing behavioral training. The best that can be done in cognitive training is thus to attempt to blind participants to the intent or purpose of the training (e.g., using an inert control training experience that participants might find plausible as an active intervention). Yet, because such control training experiences necessarily differ in key ways from the active training experiences, it has nevertheless been suggested that participants in cognitive training studies: (1) regularly intuit their condition based upon the characteristics of the given training experience; (2) understand the expectations associated with the condition; and (3) show improvements that are rooted purely in these expectations. Despite this suggestion appearing frequently in commentaries over the past several years, there currently exists very little empirical data that directly tests the hypothesis that placebo effects alone can drive positive changes in cognitive training setups. Here we propose to overcome this fundamental gap in the field with a large-scale research study designed to explicitly examine placebo effects in cognitive training. In particular, taking lessons from outside domains that have more rigorously examined the induction of placebo effects, we will utilize both ?pure expectation? methods (i.e., verbally telling the participants that an inert training protocol will enhance their cognitive functions) and ?associative learning? methods (i.e., pairing training with subjectively experienced improved performance) in the attempt to purposefully drive maximal amplitude placebo effects. We will examine the potential for such effects across different age groups (younger and older adults), across cognitive domains (e.g., fluid intelligence, working memory, selective attention), and across research sites (UW-Madison, UC-Irvine, UC-Riverside) in order to maximize generalizability. Finally, as outside domains have shown that there can be massive individual differences in the extent of placebo-responsiveness, we will also examine a selected set of individual difference variables as possible predictors of these differences. This research will provide a unique and foundational dataset that addresses directly and in a rigorous manner whether cognitive training effects can be explained by, and/or augmented by, placebos.